Taking this a bit farther, here are some simple examples illustrating stability and static determinacy.

Imagine a single weight dangling from two strings of roughly equal lengths attached near other on the ceiling. The weight will swing if you blow on it. If you turn the strings into (lightweight) compression elements and turn the whole thing upside down, it will be a bipod. The weight will indeed be balanced, but any slight perturbation will knock it over or will at least require shear forces to avoid this fate.

Now try this with three strings. The weight will resist swinging if you blow on it, and the cathedralized version is a stable tripod.

Now try four strings. If the string model is imperfect, one string might be slack. If you cathedralize it, you get a quadropod, and, if the construction is at all imperfect, the loads on the four legs might be wildly different and, if it’s too far off, the structure might wobble. This structure is statically indeterminate.

There is, strictly speaking, nothing strictly wrong with static indeterminacy, but it makes the analysis considerably more complicated.